Cabinet hardware is pretty straight forward but I want to provide potential buyers with some definitions so that they can more effectively communicate with the person selling them the hardware.
Here are some basic definitions:

Cabinet knobs are both decorative and functional in nature. Most cabinet knobs are 1-1/4" in diameter and are used to accent the style of your cabinets. Some knobs that are smaller (think of the drawer on a jewelry cabinet) and others can be larger (knobs, with some modifications, are being used as tie backs for draperies). Most knobs are round but some are square, rectangular, or organically shaped. There are many options in style , finish and size. Just pick what you like and remember, cabinet hardware, including knobs and pulls are sometimes called the "jewelry" of your kitchen or bath.

Cabinet pulls (sometimes called cabinet handles or drawer pulls) are also decorative and functional. Pulls are usually used on larger cabinet doors or on cabinet drawers. Pulls have been getting larger as kitchens have become larger. Pulls are measured by the distance between the screw holes and the most popular sizes are 3" and 96 mm (almost 4"). The overall length will be slightly longer, usually about an inch longer than the center to center distances. Remember, to measure twice or even three times - you don't want to drill holes in your cabinets and then find out that your pulls are a different size.

Appliance pulls (sometimes referred to as Sub-Zero handles, refrigerator handles or oversized pulls) are extra large cabinet pulls that are used for appliances such as refrigerators and dishwashers. As kitchens have gotten larger, appliance pulls are also being used on the larger cabinet drawers where you store your pots and pans. Appliance pulls really add to the beauty and scale of your kitchen, especially if you have larger cabinet doors and drawers.